<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../../vue.js"></script>
  <style>
    .box {
      width: 200px;
      height: 200px;
      background: yellowgreen;
    }

    .custom-appear-active-class {
      transition: all 3s;
    }

    .custom-appear-to-class {
      font-size: 50px;
    }
  </style>
</head>

<body>
  <div id="app">
    <transition appear 
    appear-class="box" 
    appear-active-class="custom-appear-active-class"
    appear-to-class="custom-appear-to-class"
    >
      <div id="box" >
        gp18
      </div>
    </transition>

  </div>

  <script>


    var vm = new Vue({
      el: "#app",
      data: {
        show: false
      }
    })
  </script>

</body>

</html>